1. Field of the Invention
The present general inventive concept relates to a method and device used in a hearing test, and more particularly to a method and device which can improve accuracy of the hearing test, compared to conventional measurements of a left/right auditory threshold.
2. Description of the Related Art
When a disorder occurs in a human ear, including any part of the outer ear, the middle ear, and the inner ear, a person cannot hear sounds very well. The resulting condition caused by this disorder is commonly referred to as being “hard of hearing.” Such a condition of being hard of hearing may be divided into conductive hearing loss, sensorineural hearing loss, and mixed hearing loss. The conductive hearing loss occurs when eardrum-to-nerve transmission is not operative due to a weak cochlea or nerve function. The representative example of being hard of hearing due to conductive hearing loss is tympanitis. The sensorineural hearing loss occurs when an audible sound is not received due to a malfunction of an auditory nerve's own function, and representative examples of the sensorineural hearing loss includes sudden hearing loss, noise-induced hearing loss, presbycusis, or the like. The mixed hearing loss is caused by the factors of the conductive hearing loss and the sensorineural hearing loss, and may be caused by congenital or acquired developmental abnormality or ear diseases.
Nowadays, the number of patients suffering from being hard of hearing is increasing year after year. The increase in people suffering from noise-induced hearing loss is due to several factors, such as frequently being exposed to a high strength sound due to an increase of environmental noise, sound media, such as an mp3 player, etc. Also, the number of patients suffering from presbycusis and being hard of hearing due to chemical abuse or environmental pollution have steadily increased with years. At the present time, it is assumed that the hard of hearing population is about 10% of the world population, including Korea.
In general, a hearing test includes two methods: a descending method of carrying out measurement while gradually lowering the level from a high level (strength) at which a subject can clearly hear a sound, with respect to 6 frequency bands, that is, 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz, and 8000 Hz; and an ascending method of carrying out measurement while gradually increasing the level from a low level at which a subject cannot hear a sound. In determining a minimum auditory threshold, the descending method shows a lower result by about 5-10 dB (decibel), as compared to the ascending method. In these hearing test methods, a tester selects a frequency, sends the subject a test sound at the frequency, and obtains a result indicating whether the subject responded or not. In other words, the results indicate whether the subject heard the test sound at the respective test frequencies.
In a conventional hearing test, since it is possible to anticipate the loudness of the following sound within the same frequency, the accuracy of the test is diminished. Furthermore, the test requires considerable time in the processes in which the tester directly selects a frequency, controls the output of a test sound, and obtains a response from a subject. Also, such a long test time may hurt the subject's concentration, thereby reducing the test accuracy, and this reduction of test accuracy is more significant in patients suffering from presbycusis.
Meanwhile, there is another hearing test method, involving the automatic selection and application of test frequencies at uniform intervals, which can be carried out in a simpler manner. However, due to the regular interval between sounds, it is possible to expect a point of time when a test sound is output. Also, it is possible to approximate and expect a point of time when the following test sound is output by noting a point of time when a current output test sound ends. Moreover, the monotony by a uniform sound length may reduce concentration. Accordingly, an easier and more accurate hearing test method is urgently needed.